Using your wrench or socket, loosen the bleeder screw on the brake caliper about a quarter of a turn. WIth the vacuum attached to the bleeder valve, turn the vacuum on, and suck the fluid out.

Reverse-bleeding is simply enough: Open your master cylinder, empty it of fluid, fill a syringe with fresh fluid, connect it to your caliper's bleed screw with a length of hose, and slowly but ...